Fundamental shift in vitamin B12 eco-physiology of a model alga demonstrated by experimental evolution
Wheeler, Glen L
Nature Publishing Group on behalf of the International Society for Microbial Ecology
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Helliwell, K., Collins, S., Kazamia, E., Purton, S., Wheeler, G. L., & Smith, A. (2014). Fundamental shift in vitamin B12 eco-physiology of a model alga demonstrated by experimental evolution. ISME Journal, 9 1446-1455. https://doi.org/10.1038/ismej.2014.230
A widespread and complex distribution of vitamin requirements exists over the entire tree of life, with many species having evolved vitamin dependence, both within and between different lineages. Vitamin availability has been proposed to drive selection for vitamin dependence, in a process that links an organism’s metabolism to the environment, but this has never been demonstrated directly. Moreover, understanding the physiological processes and evolutionary dynamics that influence metabolic demand for these important micronutrients has significant implications in terms of nutrient acquisition, and in microbial organisms, can affect community composition and metabolic exchange between coexisting species. Here, we investigate the origins of vitamin dependence, using an experimental evolution approach with the vitamin B12-independent model green alga Chlamydomonas reinhardtii. In fewer than 500 generations of growth in the presence of vitamin B12, we observe the evolution of a B12-dependent clone that rapidly displaces its ancestor. Genetic characterization of this line reveals a type-II Gulliver-related transposable element (GR-TE) integrated into the B12-independent methionine synthase gene (METE), knocking out gene function and critically altering the physiology of the alga.
Algae, Experimental Evolution, DNA Transposon, Gene loss, Vitamin B12
This work was supported by BBSRC grant: BB/I013164/1.
External DOI: https://doi.org/10.1038/ismej.2014.230
This record's URL: https://www.repository.cam.ac.uk/handle/1810/246415